This invention relates to methods of making nanoparticle wires. More particularly, this invention relates to a method of making self-assembled nanoparticle wires by a discontinuous evaporation-driven colloidal deposition method.
Nanostructured materials have received substantial attention recently due to their immense potential in technological applications. Important advances regarding the fundamental properties of nanoparticles have been reported. Reference is made, e.g., to Colvin, V. L.; Schlamp, M. C.; Alivisatos, A. P., Nature 1994, 370, 354; and Collier, C. P.; Saykally, R. J.; Shiang, J. J.; Henrichs, S. E.; Heath, J. R., Science 1997, 277, 1978. While important advances regarding the fundamental properties of nanoparticles have been made, research is being conducted to provide advanced nanoassemblies that may bring a wide range of innovation in optical and electronic devices. See, e.g., Mirkin, C. A.; Letsinger, R. L.; Mucic, R. C., Storhoff, J. J., Nature 1996, 382, 607; Shenton, W.; Davis, S. A.; Mann, S., Adv. Mater. 1999, 11, 449; and Hermanson, K. D.; Lumsdon, S. O.; Willimas, J. P.; Kaler, E. W.; Velev, O. D., Science 2001, 294, 1082. A common and simple technique to assemble nano-particles into functional structures is dip coating. This technique is disclosed, e.g., in Bhatt, K. H.; Velev O. D. Langinuir 2004, 20, 467; and Norris, D. J.; Vlasov, Y. A., Adv. Mater. 2001, 13, 371. Sol-gel dip coating has been recently developed as a depositional method at air-water-substrate interfaces for preparing nanoparticle thin films. Reference is made, for example, to S. H. Im, Y. T. Lim, D. J. Suh and O. O. Park, Adv. Mater. 14, 1367 (2002); and Iskandar, F.; Abdullah, M.; Yoden, H.; Okuyama, K., J. Appl. Phys. 2003, 93, 9237. Preparation of nanoparticle thin films using a deposition method referred to as “Evaporation-Driven Colloidal Deposition” is disclosed in J. J. Diao; F. S. Qiu; G. D. Chen and M. E. Reeves (2003) J. Phys. D Appl. Phys. 36, L25.
The formation of microwires from nanoparticle suspensions is described in Hermanson, K. D.; Lumsdon, S. O.; Williams, J. P.; Kaler, E. W.; Velev, O. D., Science 294, 1082-1086 (2001). The article describes the assembly of microwires by dielectrophoresis from aqueous suspensions of metallic nanoparticles, wherein the wires are formed in gaps between planar electrodes disposed on a substrate.
U.S. Pat. No. 6,333,200 to Kaler and Velev discloses a miniaturized immunosensor composed of a substrate having fabricated patterns forming microelectrodes with microscopic gaps between the electrodes, and colloidal latex particles dielectrophoretically deposited in the microscopic gaps. The particles have thereon biospecific molecules that specifically bind and collect target molecules.
In Park, S.; Taton, T. A.; Mirkin, C. A., Science 295, 1503-1506 (2002), a DNA array detection method is reported wherein the binding of oligonucleotides functionalized with gold nanoparticles is said to lead to conductivity changes associated with target-probe binding events. The article teaches that selective binding occurs between a shorter “capture” oligonucleotide strand located in the gap between two fixed microelectrodes and longer “target” oligonucleotide in solution. The target oligonucleotide has contiguous recognition elements that are complementary to the capture strand on one end and on the other to oligonucleotides attached to Au nanoparticles. Therefore, when the device with the pair of electrodes is immersed in a solution containing the appropriate probe and target, Au nanoparticle probes fill the gap.
U.S. Pat. No. 6,861,221 to Mirkin et al. discloses methods of detecting a nucleic acid involving contacting the nucleic acid with one or more types of particles having oligonucleotides attached thereto. The oligonucleotides may be bound to the particles through a sulfur linkage.
U.S. Pat. No. 6,781,166 to Lieber, et al. and U.S. Published Application No. 20030200521 to DeHon et al. describe the use of nanowires made out of rod-shaped nanoparticles. The Lieber et al. patent discloses that the nanowires can be arranged in crossbar arrays using chemically patterned surfaces for direction, via chemical vapor deposition. The patent further teaches that chemical vapor deposition also can be used to form nanotubes in arrays in the presence of directing electric fields, optionally in combination with self-assembled monolayer patterns.
All of the publications and patents cited above are hereby incorporated by reference herein.